CYCLONE Gita has forced emergency services to issue evacuation warnings and close roads in major urban centres as the authorities brace themselves for devastating winds and sea surges during the Tuesday rush hour.

Cyclone Gita is likely to make landfall in the upper South Island/Cook Strait area.

Though initially referred to as a tropical cyclone, the Joint Typhoon Warning Center have declared Cyclone Gita "extra-tropical" - with winds equal to a category 2 tropical cyclone - at latitude 35.5S.

New Zealand’s fire and emergency service have warned residents to secure loose items on their properties, clear drains, formulate an evacuation plan, and stay inside until further notice.

The MetService says it expects Cyclone Gita to split into two as it moves over the South Island tonight.

A spokesperson said it is typical for the Southern Alps to divide low pressure systems.

The larger storm is likely to thrash the Banks Peninsula while a smaller storm will hover over the South Island's west coast.

Prime Minister Jacinda Ardern told reporters at Parliament that military had been deployed to areas likely to be worst hit and the country's national Civil Defence office in Wellington was on standby to help local authorities.

She said: ”My message still to people is please look out for your local warnings and expect disruption to travel and please just be careful.

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Cyclone Gita was the most intense tropical cyclone to impact Tonga since modern records began

The cyclone had since been downgraded to a storm, but forecasters warned it was still likely to wreak havoc as it traversed the centre of New Zealand, parts of which were still reeling from a huge storm that prompted authorities to declare of states of emergency at the start of February.

Transport authorities shut a stretch of highway along the east coast of the South Island and the Department of Conservation closed picturesque seaside hiking tracks and campsites along the West Coast, ushering tourists away from low-lying areas.